The procedures described in the following three steps are normally beneficial to your vehicle. However, if any damage occurs to your vehicle from following this instructable, the author cannot be held responsible.
Step 1: Exterior Cleaning
Now that you have the perfect amount of suds and water, it is time to commence washing your car.
DO NOT WASH YOUR CAR ON AN EXCESSIVELY HOT OR SUNNY DAY! THE WATER WILL EVAPORATE TOO QUICKLY AND YOU WILL GET SOAP SPOTS ON YOUR CAR! WAIT FOR A COOLER, OVERCAST DAY!
As long as the day is cool and overcast, begin by rinsing down your car. It doesn't have to be extremely thorough, but start at the top of your car and rinse down along the sides. This is to remove any large particles of sediment that could scratch your paint when you begin scrubbing. It also helps to cool the body of your car, which will keep the water from evaporating more rapidly than usual.
When you begin washing your car, keep in mind the zones of washing, shown in the pictures below. Begin washing by rinsing the roof of your car with water, absorb some suds/water in your sponge or rag, and begin washing the roof in tight scrubbing circles. Go row by row across the roof section of your car. Keep the scrubbing rows parallel and overlapping, to prevent any gaps of uncleanliness. Once you are finished with the roof section of your car, rinse it thoroughly to remove the soap you used to scrub the dirt off.
Repeat the above paragraph, going section by section, top to bottom on your car. For me it goes: Roof>Windows and Roof Supports> Top of Hood and Upper Quarter panels> Middle of Doors and Trunk> Front Bumper, Lower Quarter Panels, Lower Doors, and Back Bumper. There is a reason beyond organization for this method of washing. When you drive your car, you pick up the heaviest and largest sediment on the frontal/lower surfaces of your car. You collect the lighter and smaller sediment on the Rear/Upper surfaces of your car.
Finally, when replenishing your soap supply in your sponge, wring it out anywhere except over your water bucket. If you do wring it out over your water bucket you will put all of the dirt you just scrubbed of straight into your water. Thus, when you scrub again, your putting dirt back on your car.